As regards online shopping on WWW (World Wide Web), several successful examples have been reported in the fields including travel, books, CDs (Compact Disks) and employment information, which is expected to increasingly develop in future. This form of online shopping is shifting from merely exhibiting merchandise as in the conventional HTML (Hyper Text Markup Language) files or DB (DataBase) and CGI (Common Gateway Interface) to retrieving multiple sites as a single unit and to learning users' taste to find appropriate goods, etc. An agent technology is well suited to address these new online shopping approaches. For instance, an information retrieval agent for each user and an information providing agent for each company which opens a shop can be generated to interact to enable information retrieval and sale of merchandise. While these agents may be moving agents, they act together on one site (agent server) at least temporarily.
To exchange messages between agents in such a way so that they can interact, there must be common rules for interaction between them. Accordingly, if a type database defining the rules for interaction between agents is established on an agent server (see IBM TDB Vol. 40 No. 12, pp. 29 December, 1997, for instance) and an agent which outputs a message in compliance with the rules is generated, interaction is possible on the agent server with other agents which are also in compliance with the rules.
Attempts are being made to standardize interaction between agents, such as KQML (Knowledge Query Manipulation Language) and ACL (Agent Communication Language). While a set of messages which can be used by agents is predefined in either of them, differences are found in the types of provided methods and the ways of formulation. In KQML, in addition to primitive messages such as “questions” and “answers,” a series of messages called “facilitator messages” are provided to have a mediator search an agent for the other party. In ACL, only primitive messages are provided, but the way to formulate constraints among messages is more strict and formulation by using an operator to represent a psychological state of an agent is attempted.
To describe a little about this facilitator message in KQML, an agent which wants to have a message delivered preregisters itself to a special agent, called a “facilitator” which mediates a message from another agent. Since this facilitator sends a message to all the registered agents, it does not have a feature to change its destination according to the state at the time.
As above, the above-mentioned facilitator does not provide a message sending feature reflecting a user's taste each time. While there is also a method to send a message by explicitly specifying multiple agents, it has drawbacks including being troublesome for a user and overloading the system when many messages are specified. Accordingly, it is better to limit the number of messages to be sent according to the computer's ability. In addition, there must be a way to reflect a policy of the market in which agents operate. For instance, if an owner of a shop agent has paid more than usual for opening the shop, additional privileges may be provided, such as the service of surely sending messages to the shop. The conventional technologies do not provide these features.
Thus, an object of the present invention is to provide a message sending feature which reflects “taste” in a destination agent designated by a user.
In addition, another object is to provide a message sending feature which reflects a policy of the market in which the agents operate.
In addition, a further object is to enable the system's load to be controlled by controlling the number of messages to be sent.
Still further objects are to provide an agent technology of high usability and to provide a technology which allows diversification of services by market sponsors.